Nanopolymer

A small outline on Nanopolymers

1. SEMINAR ON SEMINAR ON
NANOPOLYMERSNANOPOLYMERS
PRESENTED BY:
RAJEEV R PILLAI
ROLL NO:07NT 163
MTECH NANO TECHNOLOGY

2. NANOPOLYMERS
The word Nano is derived from the Greek word for
“dwarf”. It is the prefix for units of 10-9. In a nutshell,
nanoscience is the study of the extremely tiny.
Nanoscience is concerned with the study of the unique
properties of matter at its Nano level and exploits them to
create novel structures, devices and systems for a variety
of different uses. Particles having sizes less than 100nm are
generally called nanoparticles. These have strikingly
different properties due to their small size and thus are
found useful in many applications. The ability to measure
and manipulate matter on the nanometer level is making
possible a new generation of materials with enhanced
mechanical, optical, transport and magnetic properties

3. INTRODUCTION
Nanopolymers in simple words are nanostructured
polymers. The nanostructure determines important
modifications in the intrinsically properties. Multi scale
Nano structuring and the resulting materials proerties
across the hierarchy of length scales from atomic, to
mesoscopic, to macroscopic is an absolute necessity. The
term polymer covers a large, diverse group of molecules,
including substances from proteins to high-strength
kelvar fibres. A key feature that distinguishes polymers
from other large molecules is the repetition of units of
atoms in their chains. This occurs during polymerization,
in which many monomers, polymer chains within a
substance are often not of equal length

4. NANOPOLYMER COMPOSITES
Polymer nanocomposites (PNC) is a polymer or
copolymer having dispersed in its nanoparticles. These
may be of different shape (e.g., platelets, fibers,
spheroids), but at least one dimension must be in the
range of 1 to 50 nm. These PNC's belong to the category of
multi-phase systems (MPS, viz. blends, composites, and
foams) that consume nearly 95% of plastics production.
These systems require controlled mixing/compounding,
stabilization of the achieved dispersion, orientation of the
dispersed phase, and the compounding strategies for all
MPS, including PNC, are similar.

5. PROPERTIES OF NANOPOLYMER COMPOSITES
•FLEXIBILITY
•OPTICALLY ACTIVE
•STRENGTH
•DURABILITY
•LIGHT WEIGHT

6. PREPARATION OF NANOPOLYMERS
Nanopolymers are prepared in many ways. The
preparation of nanofibers, core shell fibers, hollow
fibers, and tubes from synthetic polymers with
diameters down to a few a nanometers can be done in
many ways like
VAPOR CONDENSATION
II. VACUUM EVAPORATION ON RUNNING LIQUIDS
METHOD (VERL) II. ELECTRO-SPINNING

7. VAPOR CONDENSATION PROCESS
This process is used to make the metal oxide ceramic
nanopolymers. It involves evaporation of solid metal
followed by rapid condensation to form nano-sized
clusters. Various approaches to vaporize the metal can be
used and variation of the medium in which the vapor is
released affects the size of the particles. Inert gases are
used to avoid oxygen while creating nanopolymers, where
as the reactive oxygen is used to produce metal oxide
ceramic products.

8. VACUUM EVAPORATION ON RUNNING LIQUIDS
METHOD (VERL)
The vacuum evaporation on running liquids method
(VERL) is a variation of vapor condensation method.
This method is used as a thin film of a relatively
viscous material, oil, or a polymer, on a rotating
drum. Vacuum is maintained in the apparatus and the
desired metal is evaporated or spurted in vacuum.
Particles from in the suspensions in the liquid and can
be grown in the process.
 Nano-Polymers are formed by this method.

9. ELECTRO-SPINNING METHOD
•This method is the most useful method in the
manufacture of the polymers in the Nano scale
compared to the above two methods that are
described. Electro-Spinning is a process that utilizes
electrical force to produce polymer fibers from
polymer solutions or melts. The obvious advantage of
the electro-spinning technique is that, it produces
ultra-fine fibers, with huge surface-to –volume ratio,
which have great application potentials in many fields
such as protective clothing, air filtration, sensors,
drug delivery system, sensors, protective textile, and
as fiber templates for preparation of nanotubes

10. PRINCIPLE
In the electro-spinning process, the fibres are spun under a high
voltage electrical field. A polymer solution is contained in a syringe,
which is equipped with a piston and a stainless steel capillary serving
as an electrode. A grounded counter electrode (round metal plate at
the bottom) is placed down the capillary and a high voltage is applied
between the capillary and the counter electrode.
Under controlled velocity the piston on the syringe was driven down
by a motor and a droplet of polymer solution is suspended by its
surface tension at the tip of the capillary. If the free surface of the
solution is subjected to an electric field, charge or dipolar orientation
will be induced at the air-solution interface. The charge repulsion
causes a force that opposes the surface tension. If the voltage
surpasses a threshold value, electrostatic forces overcome the surface
tension, resulting in that jets are ejected from the solution and move
towards the counter electrode. During the travel to the counter
electrode, the solvent in the jets evaporates and the solidified fibers
are deposited on a substrate located above the counter electrode. So
far, fibers with diameters ranging from as low as 5nm to several
microns have been produced. It is found that the morphology and
dimension of the electros pun fibers are dependent on the process
parameters, including solution concentration and viscosity,
electrical conductivity of the solution, surface tension of the solution,
polymeric molecular weight, molecular weight distribution of
polymers, vapor pressure and boiling point of the solvent, flow rate,
intensity of electrical field, distance between the capillary and the
substrate, temperature, humidity and atmosphere etc.

11. PROCESSING PARAMETERS
In electro-spinning process, three main forces are
involved:
1. Surface tension: Favors to produce as few as
possible polymer jets in order to decrease surface are
of the polymer droplets 2. Electrical repellent force
derived from electrical charged polymer droplets:
favors to form as many polymer jets as possible. 3.
Visco-Elastic force coming from polymer: against the
deformation of polymer droplets.

12. BIO-HYBRID POLYMER NANOFIBERS
Many technical applications of biological objects like
proteins, viruses or bacteria such as chromatography,
optical information technology, sensorics, catalysis and
drug delivery require their immobilization. Carbon Nano
tubes, gold particles and synthetic polymers are used for
this purpose. This immobilization has been achieved
predominantly by adsorption or by chemical binding and
to a lesser extent by incorporating these objects as guests
in host matrices. In the guest host systems, an ideal
method for the immobilization of biological objects and
their integration into hierarchical architectures should be
structured on a nanoscale to facilitate the interactions of
biological nano-objects with their environment.

13. BIO-HYBRID NANOFIBRES BY ELECTROSPINNING
Polymer fibers are, in general, produced on a technical
scale by extrusion, i.e., a polymer melt or a polymer
solution is pumped through cylindrical dies and
spun/drawn by a take-up device. The resulting fibers have
diameters typically on the 10-µm scale or above. To come
down in diameter into the range of several hundreds of
nanometers or even down to a few nanometers, electro-
spinning is today still the leading polymer processing
technique available. A strong electric field of the order of
103 V/cm is applied to the polymer solution droplets
emerging from a cylindrical die. The electric charges,
which are accumulated on the surface of the droplet, cause
droplet deformation along the field direction, even though
the surface tension counteracts droplet evolution.

14. BIO-HYBRID POLYMER NANOTUBES BY WETTING
The basic concept of this method is to exploit wetting
processes. A polymer melt or solution is brought into
contact with the pores located in materials characterized
by high energy surfaces such as aluminum or silicon.
Wetting sets in and covers the walls of the pores with a
thin film with a thickness of the order of a few tens of
nanometers. Gravity does not play a role, as it is obvious
from the fact that wetting takes place independent of the
orientation of the pores relative to the direction of gravity.
The exact process is still not understood theoretically in
detail but its known from experiments that low molar
mass systems tend to fill the pores completely, whereas
polymers of sufficient chain length just cover the walls.

15. This process happens typically within a minute for
temperatures about 50 K above the melting temperature or
glass transition temperature, even for highly viscous
polymers, such as, for instance, polytetrafluoroethylene, and
this holds even for pores with an aspect ratio as large as
10,000. The complete filling, on the other hand, takes days.
To obtain nanotubes, the polymer/template system is cooled
down to room temperature or the solvent is evaporated,
yielding pores covered with solid layers. The resulting tubes
can be removed by mechanical forces for tubes up to 10 µm
in length, i.e., by just drawing them out from the pores or by
selectively dissolving the template. The diameter of the
nanotubes, the distribution of the diameter, the
homogeneity along the tubes, and the lengths can be
controlled.

16. APPLICATIONS
•Catalysis
•Sensors
•Filter application
•Optoelectronics
•Drug delivery
•Immobilization of proteins

17. LIMITATION
•Properties change with size &
Bonding
• Lack of controlling in drug deliveries
•Toxicity

18. FUTURE ASPECTS
•Nano composite circuit board
•Neural networks
•Optical computing
•Magneto optical storage

19. REFERENCES
^ Gudrun Schmidt, Matthew M. Malwitz (2003)
Properties of polymer–nanoparticle composites:
Current Opinion in Colloid and Interface Science 8,
103–108 elsevier.com
^ A. Greiner, J. H. Wendorff , A. L. Yarin and E.
Zussman, (2006), “Biohybrid nanosystems with
polymer nanofibers and nanotubes”, Applied
microbial biotechnology 71:387-393

20. THANKS